Hi EricR,
Fifi,
If Microsoft thinks that it can change the kernel that much and force it upon all of its Win10 users without complications, I think there will be a reckoning. Unless Microsoft somehow makes it so all current and future 64bit Windows exe can run on that Linux kernel without error, they may force people to do something drastic like stop upgrading and use potentially not so clean methods to block mandatory updates. The not so clean updates block could happen lest a pure Windows be replaced by this Lindows without user consent and then all those exe's that are not compatible cease running. That will surely make people real angry at Microsoft. Just take a walk through any decent competent tech forum after a botched update and you will get the gist if you do not now.
I'm sorry to not be a perfect English speaking guy but I don't think I said (or wrote) MSFT is currently trying to "exchange" its own kernel with (by) a Linux Kernel.
From what I heard from my friend (as a matter of fact, a very top ranking MSFT manager I used to deal with for over 30 years, so we still are very dear friends especialy since I'm retired), what he said to me that MSFT is currently working on 2 other OSes, the "lite" I already talk about that will be a "pure" 64 bit OS withoit any 32 bit code support, and the other internaly called Lindows, using a Linux 4.xx kernel and on the top of which they "port" their UI (with all its API's calls).
So, any "clean" program running on Windows 10 "should" run on this "next" OS unless they wrongly use undocumented APIs or very specific system calls.
Just to sustain such an approach: remember that the IBM Vancouver Lab "ported" the OS/2 Presentation Manager Workplace Shell from the OS/2 kernel to the DOS-Windows kernel within less than a year.
BTW, MSFT will ask more time than a year to do so because they just don't know how to code with small and efficient dev teams, the main "reason" being the place of "politics", what IBM used to call the "barons" defending their own little chapel.
Happy new year season.
Fifi